Blacknose Sharks Research Paper

Sharks are a species that get a bad name because of bull, tiger, and great whites attacking people and because of movies like jaws. Sharks descending from the megalodon which is from the dinosaur era contributes to its perception of scary and dangerous animals. Although some sharks like the Great White are dangerous to humans, others such as the blacknose sharks are not a threat to humans. Blacknose sharks are on the IUNC red list and are listed as endangered with the population trend listed as decreasing. 

Background

The blacknose sharks scientific name is Carcharhinus acronotus and is distinguished by the snout being dusty blotch at the tip, distinctly dark in juveniles and diffused dusky in adults. The other is the first dorsal fin originating over or behind the free tips of the pectoral fins. Blacknose sharks has a small and slender body with a somewhat long rounded snout and large eyes. It has a pale greenish or yellowish-grey body with black or dusty tips on the second dorsal fin and dorsal caudal lobe. The upper jaw consists of 12 to 13 rows of moderately narrow and triangular teeth with oblique cusps along with coarser serrations along the bases, becoming less notched as they moved towards the middle.  The lower jaw consists of 11 to 12 rows of cusped serrated teeth with broad bases and 1 to 2 symphyseal tooth compared to one symphyseal tooth on the top. The teeth are closely spaced and overlapping which each having 3 ridges and points that direct towards the rear.  The average size of an adult blacknose shark is 4.1 feet with a max length of 6.5 feet and typically weights 15.4 pounds to 24.2 pounds. The age of maturity in the US south Atlantic waters is 4.3 years for males and 4.5 years for females and in the Gulf of Mexico age of maturity is 5.4 years for females and 6.6 years in males. Females live about 19 years in the south Atlantic and 16.5 years in the Gulf of Mexico while males live up to 9.5 years. The blacknose shark is a quick swimmer that feeds on small fishes such as pinfish, croakers, porgies, anchovies, spiny boxfishes, porcupine fish, and octopus. Blacknose sharks mate in late June to early July and have a gestation period of 10 to 11 months. In the Gulf of Mexico, female sharks reproduce annually while those in the Atlantic reproduce every 2 years and have a litter size of 3-6. These sharks are also known to form large schools and sometimes associate with schools of mullets and anchovies. 

Threats and Future

Commercial fishing and recreational fishing is the biggest threat to blacknose sharks. They are a bycatch of longlines, gillnets, and trawls of commercial fishers and are caught by recreational fishers using hook and line.  In 2009 the US estimated 29,230 individuals were caught commercially and 1,070 individuals recreational. These sharks don’t have many safe places to escape these fishers because artisanal fisheries are intense across the southwest Atlantic and commercial trawl and longline fisheries are largely unmanaged. In Venezuela, the intense fishing and lack of management have contributed to peaks in catches followed by declines which is an indication of overfishing. The Brazil-Guianas shelf was already being over-exploited by 2000 with many vessels including ones crossing maritime borders. Despite areal closures and total allowable catch limits that were put in place, efforts have been diminished and management of the number of vessels in operation have fallen apart. Recreationally they are fished as a gamefish due to the fight it gives on light tackle. Due to this lack of management, the blacknose sharks’ future is questionable if not certainly doomed. Some groups are trying to ban land-based shark fishing to protect not only the sharks but also the local community and tourist that go to the beach. Despite these efforts, the US government and state governments refuse to ban the fishing of this shark in the Atlantic. The National Oceanic and Atmospheric Administration has proposed the 2022 annual fishing quota of blacknose sharks is 37,921 pounds with the season opening January 1, 2022. The Florida Fish and Wildlife Conservation Commission lists blacknose sharks as harvestable at 1 shark per person per day and 2 sharks for vessels and there is no minimum size requirement. These sharks are also hard to keep in confined spaces like aquariums and only a few have been able to do so effectively for extended periods. These sharks are sensitive to confined space trauma and handling stress like in the New England aquarium that caught 10 sharks over 4 years and individuals only survived for 5 months to 2.5 years. 

Management

The blacknose shark is managed by the Atlantic Highly Migratory Species Federation Management plan that was finalized in 2006 by the US National Marine Fisheries Service. This plan includes management measures including quotas and seasonal closures. Coastal gillnet bans in South Carolina, Georgia, Florida and Texas along with commercial retention on all trips when season is open provides some protection for the sharks. Central America and the Dominican Republic have banned shark finning, closed the season during the mating months, banned fishing near coral reefs, river mouths, and nursery areas. Many other counties in South America have implemented regulation as well but the biggest is Honduras declaring their territorial waters as a shark sanctuary. Future actions for this species involve research to learn more about the specifics of this species. Blake Hamilton is currently working on a project to identify the importance of the two genetically separate populations using the Florida Keys and Florida Bay area to mate and pup. He also plans to describe their seasonal movement patterns in attempt for the management strategies of this shark species to be updated. More research, especially an updated evaluation of the stock status, is desperately needed for proper management of this shark species to be done. Other possible future actions would be banning the harvesting of blacknose sharks, better regulation of vessels in the waters surrounding South America, and the banning gillnet fishing for all coastal states where this shark inhabitants which would be Louisiana, Mississippi, Alabama, North Carolina, and possibly Virginia. Another big management action that would greatly improve the protection of blacknose sharks, is to educate people about sharks in general and give them opportunities to appreciate these sharks in their natural habitat. 

Evaluation

I feel like the most important immediate management action needed for the conservation of the blacknose shark is to ban the fishing and harvesting of them. The species is already listed as endangered, and the US is continuing to let not only recreational fishing of the shark but also commercial capture of the shark. But the US is not the only country needing to ban the fishing of this species, other countries in central America and south America also need to ban the harvesting of the blacknose shark. Honduras is on the best track with the shark sanctuary which not only saves the blacknose shark but all other sharks that should be protected and appreciated. Banning the harvesting of these sharks is the best chance the population has at growing in numbers. These sharks are not able to be kept in captivity and breed up so management to increase the population of the species must be done in the wild. Additionally, if I was to choose 1 specific place to ban all harvesting of the shark, it would be their breeding grounds, the Florida Keys and Florida Bay area. Protecting where they breed and pup will give these sharks a safe place to reproduce and increase their population for both the Atlantic and Gulf of Mexico populations. Blacknose sharks deserve the best protection we can provide and the US should focus on protecting them since the Atlantic population only occurs in waters surrounding the US.